It's either your connector or else the engagement between the sear's, 'kick-plate' and the striker lug is less than 50%. So, ....... WHAT did you do? Things could get worse; i.e., 'more dangerous'. Suggest you stop shooting that G-21 and let an armorer look it over for you.
Here, take a look at this -
(75% engagement would be better)
(Bad trigger job on right.)